It is well known in the art to analyze soil samples for their helium content. Furthermore, it is known in the art to determine the ratio of radon/ helium content of such samples. These methods are all fairly rough and inaccurate and have the disadvantage of analyzing measuring the concentration of gaseous ingredients. It would, therefore, be desirable to have a geochemical and geophysical method available by which an accurate determination of an element could be carried out that is indicative for uranium concentrations and can be used to determine changes in uranium concentrations in underground formation features that simulate changes in uranium concentrations. Such a process would constitute a valuable tool in connection with other primarily geophysical data to determine the presence and absence of, e.g., uranium-enriched ores, of geothermal reservoirs, or of natural gas sources.